Piston and piston ring



1942- M. 'GERLACH mm. ,283,432

PISTON AND PISTON RING Filed Sept. 9, 1940 I Inventors 7 6er/ac/i,

Patented May 19, 1942 UNITED STATES PATENT OFFICE PISTON AND PISTON RING Manfred Gerlach, Ak-En-on-the-Elbe, and Walter Gerecke, Dessau, Germany, assignors to Junkers Flugzeug-und-Motorenwerke A. G., Dessau, Germany, a corporation of Germany Application 9 Claims.

September 9, 1940, Serial No. 356,082 In Germany July 12, 1939' of a plurality of parts so that the piston could be taken apart in order to insert or replace the fire ring. Obviously a piston composed of a number of parts is complicated and not as desirable as a single piece piston. The latter type pistons known to the prior art could not be provided with closed fire rin s inasmuch as nomeans was known for assembling a'closed fire ring with such singlepiece pistons.

An object of this invention is to produce a single unit piston construction to which a fire ring can be afiixed and replaced.

Another object of the invention is to produce a novel piston construction to which a closed fire 7 ring can be afflxed and locked in place.

the fire ring can be elastically deformed within its elastic limits to slip over the piston and become locked thereto when the ring returns to normal shape. Thus the piston head is given an oblong shape and separated from the piston body by a" circular groove. A circular fire ring can be deformed within its elastic limits to an oblong shape and slipped over the oblong head where it will be locked in the groove when the deforming force is removed. Alternately the piston ring can be given a special shape so as to be fitted to the piston when deformed, and

' then locked with the piston when returned to normal shape.

In a second form of the invention, the piston head can be provided with a resilient skirt with the fire ring holding groove lying between the skirt and the piston body. The closed fire ring can be snapped over the skirt and locked into 'place' within the groove.

The means by which the objects of this invention are obtained are more fully described with reference to the accompanying drawing in which:

Fig. 1 is a top plan view of a piston constructed according to one form of the invention.

Fig. 2 is a cross sectional view on the line IIII of Fig. 1. Fig. 3 is a cross sectional view on the line III-III of Fig. 1.

Fig. 4 is a side elevational view, partly in section of a modified form of the invention.

In Figs. 1 to 3, the piston body 2 is provided with an oblong head portion 4 separated from the piston body by a circular groove 6. Portion 4 may be considered a part of the piston itself, or

may be considered as a separate plate portion for shielding the piston from the combustion chamber. As more clearly seen in Fig. 1, head portion 4 is of elliptical shape with the major axis lying along section line IIII, and the minor axis lying along section line III-III. Piston body 2 ls circular in section as is conventional, and groove 6 is likewise of circular form with its diameter being approximately equal to or slightly less than the length of the minor axis of the elliptical shaped head portion 4.

A closed non-split fire ring 8 composed of an annulus l0 and an inwardly turned flange portion 12, is adapted to be seated upon the piston body with the flange I 2 engaged in the groove 6 to fix the fire ring in place upon the piston. It is readily apparent that fire ring 8 can be fitted upon th piston'by deforming. the annulus II! and flange l2 so that they assume an elliptical shape corresponding to the shape of the head portion 4 whereupon the fire ring is slipped over the head portion, the deforming force released. and the flange I2 engaged beneath the overhanging portions of the upper part 4. Of course. the fire ring 8 is only deformed within its elastic limit so that it resumes its original shape as soon as the deforming pressure is released. Conse- V quently fire ring 8 is afiixed to a one-piece piston. and no portion of the piston'has to be removed in'order to replace fire ring 8. The fire ring is positively held in place, and is also adjustable with respect to the piston body.

I In the embodiment of the invention as shown in Fig. 1, piston body I4 has a head portion Hi from the outer periphery of which depend a number of spaced resilient flanges l8 forming an shaped closed fire ring 22 is adapted to be seated. It is apparent that fire ring 22 can be assembled with the piston by slipping fire ring 22 down over head portion l6, and forcing the ring over elastic flanges l8 which give inwardly toward the body l4. When ring flange 22 gets below th lower edges of flanges It, the latter flanges snap back into their original position and secure the ring l8 in place; 01 course, flanges I8 are integrally formed with head portion l6 and are deformed only within their elastic limits so that they will snap back in place after the ring 22 has been seated in the groove.

It is therefore apparent that the objects of the invention are achieved in that a single-piece integral piston can be provided with a closed non-split fire ring. No necessity exists for forming the piston in more than one piece, or of taking th piston apart, in order to afilx the fire 9 less than that of said skirt.

ring to the piston.

Having now described the means by which the objects of'the invention are obtained, we claim:

1. A piston for an internal combustion engine comprising a piston body, a head member for said body and cooperating therewith to define a groove extending peripherally of said body, a closed fire ring member having a non-conforming shape with respect to said head member, and at least one of the two named members being deformable within its elastic limit into conformity with the shape of the other member whereby one member may be slipped over the other to seat said ring member in said groove.

2. A piston for an internal combustion engine comprising a piston body of circular section, a 40 piston head of non-circular section, a peripheral- I 1y extending circular groove in said body between silient skirt depending from the periphery of said head and cooperating with said shoulder to form a groove, and a closed fire ring having a diameter less than the diameter of said skirt and seated in said groove, said skirt being deformable within its elastic limit to permit passage of said ring over said head into said groove.

6. A piston as in claim 5, said skirt comprising a plurality of spaced resilient flanges.

7. A piston as in claim 5, said ring being composed of an annular member and an inwardly extending flange, said flange having a diameter 8. A piston as in claim 2, said fire ring being composed of an annular member and an inwardly extending flange, said flange having a diameter less than the major axis of said head.

9. A piston for an internal combustion engine comprising a piston body, a head member for said body and cooperating therewith to define a groove extending peripherally of said body, a closed fire ring member, and at least one of the two named members beingdeformable within its elastic limit into conformity with the shape of the other member whereby one member may be slipped over the other to seat said ring member in said groove.

MANFRED GERLACH. WALTER GERECKE. 

